lk/writing/ed.md

title, tags

title	tags
Ed: The Standard Editor	writing guide

ed was designed for real terminals, i.e. a typewriter. You would type a command to the computer, and it would type out any errors. It would not waste paper, ink, and time by typing out COMMAND RUN SUCCESSFULLY after each command. A silent machine meant a happy machine.

Basic Usage

Open a file:

ed file.md

Insert a new line.

1. Press i<Return>
2. Type the line.
3. Finish your edit with single dot.

i
dear diary,
.

Print the current line:

p

Change the current line:

c
Dear diary,
.

Delete the current line:

d

Write the 'buffer' to disk:

w

Quit:

q

Working with Lines

Open that file:

ed file.md

Add a line:

a
Fortune of the day:
.

Run fortune, and place the results inside the current buffer:

r!fortune
?

The ? indicates an error. We can ask what the error was with the command h:

r!fortune
?
h
Unexpected command suffix

The command r has something after it which makes no sense. It should have a space after the r!

r !fortune
42

That last line means ed has 42 characters in its buffer.

Read the current line, and show the line number:

n
2	How many weeks are there in a light year?

This means we are on line 2.

Fill up the file with fortunes:

r !for x in 1 2 3 ; do echo --- && fortune ; done

Print out which line in the file we are currently on:

=
12

There are twelve lines. Go back up to line 3:

3
---

So line 3 just has our delimiter: ---.

Whenever you hit enter, ed prints the current line then moves to the next line.

I would have promised those terrorists a trip to Disneyland if it would have

gotten the hostages released.  I thank God they were satisfied with the

missiles and we didn't have to go to that extreme.

Go back a few lines:

-3

Print out 'current line', using the dot:

.

Print current line with the number of that line:

.n
11	Possessions increase to fill the space available for their storage.

Print and number the next three lines:

.,+3n
9	You have no real enemies.
10	------
11	Possessions increase to fill the space available for their storage.

Skip ahead four lines:

+4
?
h
Invalid address

This is an invalid address because there are no more lines, so ed cannot print them.

All Commands

Meta Commands

Aim	Command
Explain an error (?)	h
Show a prompt when ed can take a command.	P
Change the default filename to rec.txt.	f rec.txt
Save the file.	w
Append a line after line 8.	8a
Move three lines down.	+3
Move four lines back.	-4
Move to the last line.	$

Create

Aim	Command
Insert a line before line 5.	5i
Append a line after line 8.	8a
Read all of ~/.profile into the current position.	r ~/.profile
Run dir and place the results into the current position.	r !dir
Copy lines 10 to 15 to line 23.	10,15t23

Read

Aim	Command
Print current line.	. or p
Read lines 1 to 10.	1,10p
Print and number lines 2 to 7.	2,7n
Find the next line ending with fi	/fi$/n
Show the number of the next line starting with if.	/^if/=
Find the line which contains HOME.	?HOME?
Print the next five lines literally (showing tabs).	.,+5l
Print from here till the end of the file.	.,$p
Show all lines with HOME and show their numbers.	g/HOME/n

Update

Aim	Command
On line 30, substitute less with less -R	30s/less/less -R/
Change each line starting # to ##	,s^# /## /g
Move lines 50 to 55 to line 20.	50,55m20

Delete

Aim	Command
Delete line 4.	4d
Delete from here to four lines down.	`.,+4d
Delete all lines starting with #.	g/^#/d